1. Field of the Invention
The present invention is a PROCESS FOR OBTAINING PIPES AND CONNECTIONS FROM A POLYMERIC COMPOSITE, which was developed with the purpose of providing non-metallic pipes and connections made of a polymeric composite material, for application in surge flow lines of oil wells, injection of fresh water, injection of salt water, injection of produced water and injection of CO2 in the oil production fields, whose structural characteristics provide support against mechanic impacts and wheel loads, provide protection against elements of the environment, allow a maximum fluid temperature of 95° C., allow an operative pressure of from 500 to 3000 PSI, protect against electrochemical corrosion and abrasive wear provoked by silica in a suspension produced by the fluid (water, oil and gas) arising from the oil well. This technologic innovation replaces the metallic surge flow lines of wells that are currently made of material API 5L GR B.
2. Discussion of the Related Art
For the production of crude oil (oil, gas and water), oil companies currently use aerial surge flow lines of steel API 5L GR B having a diameter of 3 inches, that permit a maximum pressure of 1000 psi and a maximum operation temperature of 65° C. These lines are widely used, and installed in thousands of kilometers. These production installations are subject to atmospheric corrosion and electrochemical corrosion in accordance with the environment and fluids produced in the oil wells. Many of these wells are considered critical due to the fluid produced that provokes high premature wear and internal corrosion in the metallic surge flow lines. Some of these lines, depending on the composition of the fluid produced, start leaking after less than one year of operation due to internal corrosion.
The pipes used in the surge flow lines, especially ones made of steel, are subject to deterioration, both by mechanical action (wear) and by chemical or electrochemical action (corrosion), or by the joint action of both.
With regard to internal corrosion, the oxygen present in the water vapor contained in the atmospheric air is one of the main factors responsible for oxidation and it is universally present, including on the inside of the pipe. Therefore, it promotes oxidation mainly in the form of pits (cavities having an angular shaped bottom and a depth greater than its diameter) that decrease the life span of the pipe. This type of corrosion is responsible for approximately 20% of the total corrosion that occurs in the pipe.
The internal corrosion of the metals near the coast is a process that occurs due to the presence of salts dissolved in the water droplets, which forms an electrolyte solution. With the increase of electric charge flow (ions) in the solution, there is a potentiation of the corrosion process due to the oxidizing power of the oxygen in the atmospheric air. In the case of pipes, the external corrosion is presented uniformly, being the main manner of loss of mass of the pipe (around 80%), because it is presented in the whole exterior surface. A uniform loss of thickness of the exposed layer occurs.
Due to the problems caused by metal pipes, pipes, pipes formed of fiberglass with epoxy resin have been used with success in highly aggressive environments, where steel and its alloys last for only weeks or months. The exceptional resistance to corrosion of the composite of these materials, even when in contact with alkaline, acid, and solvent environments have been affirmed and well documented for decades. The extremely high chemical resistance of the pipes allows their application in most cases in which the conventional materials are destroyed by corrosion. They do not require cathodic protection due to their very low electric conductivity.
The composite constructed with fiberglass with epoxy resin offers lightness, good mechanical properties and exceptional chemical inertia in a broad range of aggressive environments.
However, pipes made from fiberglass may only be used underground, thus, ditches having an average depth of 60 cm and width of 40 cm should be provided, observing that the ditches should not have hard rocks and particles therein, as these hard rocks and particles may come into contact with the pipes and damage them. It is therefore necessary for the ditches to have a layer of sand in the bottom, where the pipes are deposited and the pipes then covered with another layer of sand. Only then may the material removed from the ditch be placed (backfill).
When it becomes necessary for an aerial stretch to cross-streams or other obstacles, the pipes are jacketed. This is both for the protection of the fiber pipe against solar beams and for protection against vandalism. This jacketing is later painted and has indicative inscriptions regarding the material being transported, the pressure, etc. The jacketing covers the whole aerial part and penetrates at least 50 cm into the ground. To avoid contact with the jacketing, the pipes are protected through rubber strips.
Despite its good applicability in relation to corrosion, those pipes have a low resistance to impact, and they may only be used underground in deep ditches in order to avoid such impact by wheels. This contributes to an increase of the project's cost.
For its low resistance to                impact, the fiberglass pipes are not used in surge flow lines, thus obliging the oil companies to use metal pipes, which require constant maintenance and stoppage of lines causing financial losses.        